Geoscience Reference
In-Depth Information
Today much is made of whether scientists have reached consensus on the ques-
tion of global warming. But the history we have reviewed shows that the peer-re-
viewed literature is a much better gauge of the true state of a science than the elu-
sive concept of consensus.
During the first half of the twentieth century, that the continents had not drifted
and that there were few if any impact craters on the Earth or the Moon had become
accepted wisdom, matters beyond discussion. Yet in both cases the consensus
turned out to be wrong. But what if one had judged the state of the two theories not
from what scientists said but instead from what they published in peer-reviewed
journals? From the 1920s through the 1950s there were few papers on either drift
or meteorite impact, and those few presented at least as much evidence for each
theory as against it. A fair judgment from the scientific literature of the period,
and thus based on publishable evidence, would have been that instead of a con-
sensus against continental drift and meteorite impact, there was something closer
to a toss-up.
What of global warming? From the turn of the nineteenth century until the
mid-1950s, the magisters of meteorology were satisfied that Ångström had falsi-
fied Arrhenius's CO
2
theory. Yet that consensus also turned out to be wrong. Most
of the verdicts against the theory appeared in topics and review articles, where au-
thors can say whatever they like. But again, ask what the peer-reviewed literature
showed, and you would reach a different conclusion. The few articles that did ap-
pear on the CO
2
theory were largely opinion pieces and provided almost no new
evidence. Instead we find the papers by Hulburt and Callendar, which showed that
the CO
2
theory was at least possible, though no one took notice.
In each of the three cases, scientists had enough information to lead them to
question the consensus, but few did, and they were ignored. The fourth discov-
ery, the age of the Earth, was different. Here too there was an overwhelming
consensus—that the Earth can be no more than 100 million years old—and it
too turned out to be wrong. In this case, however, the scientific literature upheld
the consensus view, since without knowing about radioactivity, scientists had no
choicebuttousetheirflawedhourglasses.SomehadanintuitionthatKelvin'stime
allowance was insufficient to fund geology, but they had no contrary facts to back
it up.
Conclusion
My friend Ed was half-right: of course scientists have been wrong before. But they
did not stay wrong. As new data arrived, scientists changed their position, some
